Date: Thu, 16 May 2019 11:03:16 +0300 From: "Andrey V. Elsukov" <bu7cher@yandex.ru> To: Peter <pmc@citylink.dinoex.sub.org>, Miroslav Lachman <000.fbsd@quip.cz> Cc: freebsd-fs@freebsd.org Subject: Re: Waht is the minimum free space between GPT partitions? Message-ID: <1f98b517-e5f9-42a6-d900-246d83972b55@yandex.ru> In-Reply-To: <20190516003607.GA93284@gate.oper.dinoex.org> References: <20190515204243.GA67445@gate.oper.dinoex.org> <60d57363-eb5c-e985-82ad-30f03b06a4c6@quip.cz> <20190516003607.GA93284@gate.oper.dinoex.org>
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This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --9KTc7VChSqok7dg6pfdMDtudqnBpBLyYe Content-Type: multipart/mixed; boundary="E2vuBo1t11Ma6gyusTMj4pUypHS0GcXh7"; protected-headers="v1" From: "Andrey V. Elsukov" <bu7cher@yandex.ru> To: Peter <pmc@citylink.dinoex.sub.org>, Miroslav Lachman <000.fbsd@quip.cz> Cc: freebsd-fs@freebsd.org Message-ID: <1f98b517-e5f9-42a6-d900-246d83972b55@yandex.ru> Subject: Re: Waht is the minimum free space between GPT partitions? References: <20190515204243.GA67445@gate.oper.dinoex.org> <60d57363-eb5c-e985-82ad-30f03b06a4c6@quip.cz> <20190516003607.GA93284@gate.oper.dinoex.org> In-Reply-To: <20190516003607.GA93284@gate.oper.dinoex.org> --E2vuBo1t11Ma6gyusTMj4pUypHS0GcXh7 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 16.05.2019 03:36, Peter wrote: > On Thu, May 16, 2019 at 12:29:16AM +0200, Miroslav Lachman wrote: > ! > I found, if I put partitions directly together (so that another sta= rts > ! > immediately after one ends), under certain circumstances the volume= s > ! > become inaccessible and the system (11.2) does crash. Obviousely th= ere > ! > is a safety distance required - but how big should it be? > !=20 > ! I read your post on forum=20 > ! https://forums.freebsd.org/threads/create-degraded-raid-5-with-2-disk= s-on-freebsd.70750/#post-426756 >=20 > Hi, great, that should explain how to make it happen. >=20 > ! No problems for years. >=20 > Me neither with MBR/packlabels, but only recently switched to GPT. >=20 > I suppose either GPT or ZFS-autoexpand seems to go out-of-bounds; I > couldn't determine which. >=20 > ! I think your case is somewhat different if you split disk in to 3=20 > ! partitions later used as 3 devices for one ZFS pool, so maybe there i= s=20 > ! some coincidence with expanding ZFS... and then it is a bug which sho= uld=20 > ! be fixed. >=20 > If we could fix it that would be even better! Agreed, it's an ugly > operation, but I love to do ugly things with ZFS, and usually it > stands it. ;) >=20 > ! Can you prepare some simple testcase (scriptable) which make a panic = on=20 > ! your host? I will try it in some spare VM. >=20 > The description in mentioned forum-post is pretty much what I did. >=20 > At first I did it on my router, as there is empty space on a disk, > and when that had gone by-by, I tried it on the desktop with an > (otherwise empty) USB stick. Takes an eternity to create ZFS-raidz > even on USB-3 stick - they are not designed for that - but the outcome > was the same. >=20 > Procedure is: > 1. create new GPT scheme on stick. > 2. add 3x 1G freebsd-zfs partitions with 1G -free- in between. > 3. zpool create test raidz da0p1 da0p2 da0p3 > 4. resize 3x partitions to 2G each > 5. zpool set autoexpand=3Don test > 6. export the pool > 7. zpool online When you exported the pool, ZFS is able to find its labels on the entire da0 disk. This is probably leads to panic, and not because there are no free space between partitions. When panic happens, just make a photo of panic screen, in most cases it can say where is the problem. Even better, if you add debug options to the kernel and then you will be able get core dump. --=20 WBR, Andrey V. Elsukov --E2vuBo1t11Ma6gyusTMj4pUypHS0GcXh7-- --9KTc7VChSqok7dg6pfdMDtudqnBpBLyYe Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Comment: Using GnuPG with Thunderbird - https://www.enigmail.net/ iQEzBAEBCAAdFiEE5lkeG0HaFRbwybwAAcXqBBDIoXoFAlzdGUQACgkQAcXqBBDI oXoboAf/US7SnrGfFwIBGDriHHNL+nn+kXFqQ6Z7IPycpKqYp0iF4sfUuWNa3BeB oFq1iSVNHAF1GSYGLFB2tjFjqrFurQSH9dDaYK6eoGjc8vCFsEt7Q8bX8bQTF/vJ MDo4f26Zy+eNZalh4SuuHHjli5pGRonr9VzI8Eaia6b/xp6u7CV/+vEOFo7Asr4/ Yult7uaA4h+mBjrsD3SCo2x6ssGkfuT7HTxFWdshgcdn4svwkRv2ounfzpamluIn lRvBfz3YCEF9Xb+j5GrtolkZPp8HhUZZfz0i6f1GWirfBoLroazy0HsHVg89J9Cm i4FQkMyKUvM9cNXG6TfDUsFHlIByHQ== =EJrx -----END PGP SIGNATURE----- --9KTc7VChSqok7dg6pfdMDtudqnBpBLyYe--
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